The Registry is a multi-centre, multi-country, non interventional, study in alpha mannosidosis patients. In connection of Lamzede marketing authorization and its Risk Management Plan, this registry is requested to obtain long term data on effectiveness and safety, furthermore, it will expand the current understanding of alpha-mannosidosis by collecting additional data on alpha-mannosidosis patients despite the therapeutic treatment they are receiving. The enrolment in the Registry will occur during an indefinite timeframe. The duration of the observation period for each patient will be of 15 years. Patients with alpha-mannosidosis receiving and not receiving treatment with Lamzede will be enrolled. If applicable in accordance with routine clinical practice, the following schedule of visits is recommended: Inclusion Visit, approximately 7 days prior to the Baseline visit, in which eligibility criteria will be checked and the informed consent form signed. Baseline Visit, corresponding to the time in which the observational period will start and when the site can also evaluate to possibly start or continue the treatment with Lamzede according to clinical practice, Six-month and Yearly follow-up visits for all patients included in the registry, Unscheduled follow-up visits, such as but not limited to, three months after Lamzede treatment start, or whenever deemed appropriate, according to treating physician’s judgement for patients that start Lamzede treatment within one year prior to Registry inclusion. During the following years, routine clinical visits are recommended to take place at least annually, for all patients. Effectiveness will be evaluated through a Global Treatment Response by aggregating single endpoints in 3 disease relevant domains: pharmacodynamics, functional and quality of life. Safety variables will be also assessed including but limiting to SAEs, ADRs, AEs leading to treatment stop and to death, ADA, IRRs hypersitivity and Acute renal failure.